Agreed, it was devastating for the characters visibility and viability and while I think Rachel recovered in the comics by 2018, but Lorna still hasn’t reached where she was in the early to mid ‘00s or anything close to that regardless of what one might feel about Morrison and Austen.
We have debated the A-C list question before and I prefer not to get into it again only to say Lorna was a much hotter and more debated character in 2004 then in any time since. Some prefer characters having their independence to grow even it it sacrifices viability. Lorna neither grew in space and it had her visibility sacrificed.
As for the other issue of Lorna and Magneto. The key is Lorna to have her own history recognized with Genosha and other events and to have a solid POV. I don't think Blue did that and wrote her as much more a blog standard X-Man to accentuate his depth. I liked Bunn's Magneto, but his Lorna came off as green haired Jean only with a higher opinion of Mags and that doesn't fit Lorna nor her history nor is it good for her. So far I see nothing wrong with what Hickman has done with Lorna, but he also hasn't done much either.
Bunn never wanted to write Blue in large part because it was oriented towards too young a readership, but editorial bribed him by letting him use his boy Magneto. If I was going to tweak Blue's story I would have had Emma much more reasonable and building New Tian and working with Lorna in conflict with a Magneto who is trying to embrace Xavier's values. None of this crazy Emma working with a Sentinel garbage.
Bunn fell into the old habit of the idea Lorna can not be philosophically harder then Magneto at a given time even when he is trying out Xavierism. Marvel should work with where it makes sense for both characters to be at philosophically based on events. Forced conflict doesn't do either of them any good, its issues that rise from within the story and the characters history that make it interesting.